Neutral molecules are transpoed by:

Absence of charge over molecules (Uncharged/Neutral molecules) ours their transpo by simple diffusion. Small neutral molecules are usually transpoed freely across plasma membranes by simple diffusion. Ref: Ganong's Review of Medical Physiology, 22nd Edition, Page 31; Biochemistry By Mary K. Campbell, Shawn O. Farrell, 7th Edition, Page 209; Harper's Textbook of Biochemistry, 27th Edition, Pages 108, 424, 433